Electricity Flashcards
What makes an object electrically neutral?
Matter is made up of atoms with equal amounts of negative and positive charges, making the object neutral.
How is static electricity created?
Static electricity is created when electrons build up on an object.
What happens when certain objects are rubbed together?
Electrons jump from one object to another. The object that gains electrons acquires a negative charge, while the other object acquires a positive charge.
Why do you get a shock after walking on a carpet and touching a metal object?
The metal discharges the static charge built up in your body, causing a shock.
Why does your hair stand on end when a balloon is rubbed on it?
Rubbing the balloon transfers electrons, causing your hair to repel due to the same charge.
What happens when objects have the same charge?
Objects with the same charge repel each other.
What causes lightning?
Lightning is caused by a huge buildup of static negative charge in clouds, which discharges through metal rods into the ground.
What is the purpose of the Van de Graff generator?
The Van de Graff generator accumulates large static charge for experiments, causing effects like hair standing on end.
How does static charge discharge?
Static charges discharge quickly when electrons return to their original positions.
What is dynamic electricity?
Dynamic electricity is a continuous flow of electrons through a wire.
What materials are good conductors and insulators of electricity?
Metals and graphite are good conductors, while wood and plastic are insulators.
What is the difference between an open and closed circuit?
An open circuit has a break in the flow of current (off), while a closed circuit allows current to flow (on).
What is the key difference between series and parallel circuits?
In a series circuit, current is the same through all components but voltage is divided. In a parallel circuit, voltage remains the same, but current is divided.
Why do bulbs glow dimly in a series circuit when more bulbs are added?
The voltage is divided among the bulbs, reducing the brightness.
Why do bulbs in a parallel circuit continue to work when one bulb breaks?
In a parallel circuit, other parts of the circuit remain closed, allowing the remaining bulbs to work.
How is voltage measured, and what is the unit?
Voltage is measured with a voltmeter in volts (V), which is connected in parallel across a resistance.
How is current measured, and what is the unit?
Current is measured with an ammeter in amperes (A), which is connected in series in the circuit.
What is the direction of conventional current?
What is the difference between AC and DC current?
AC current changes direction periodically, while DC current flows in one direction.
How does resistance affect the flow of electricity?
Resistance reduces the flow of electricity and is affected by wire thickness, material, temperature, and components.
What is Ohm’s Law?
Ohm’s Law states that V = IR (Voltage = Current x Resistance).
How does increasing voltage affect current according to Ohm’s Law?
Increasing voltage increases current.
How does increasing resistance affect current according to Ohm’s Law?
Increasing resistance decreases current.
How does current affect resistance according to Ohm’s Law?
Increasing current decreases resistance.
What energy conversions happen in common electrical devices?
Heating coil: electrical to heat; globe: electrical to light; motor: electrical to mechanical; loudspeaker: electrical to sound.
How does a loudspeaker produce sound?
An electrical field corresponding to sound creates a magnetic field, causing vibrations that produce sound.
What does the law of conservation of energy state?
Energy cannot be created or destroyed, only transformed from one form to another.
How does a generator produce electricity?
A generator turns a coil inside a magnetic field to generate electricity.
What happens when current flows through a wire inside a magnetic field?
It creates a magnetic field around the wire.
What is electromagnetic radiation?
Electromagnetic radiation spans from high-frequency gamma rays to low-frequency radio waves, including UV, infrared, and visible light.
How do electromagnetic waves travel through space?
Electromagnetic waves, such as those from the Sun, can travel across the vacuum of space.
